Scientists at the Vienna University of Technology have developed a brand new method for positioning molecules in space with micrometer precision. They call it "3D-photografting," and it uses laser beams to place microscopic chemical structures in the nooks and crannies of a macromolecular meshwork known as hydrogel.

Materials scientist Aleksandr Ovsianikov, one of the researchers responsible for the new technique, says you can think of the hydrogel like a three-dimensional canvas. The negative spaces created by its lattice-like structure provide the perfect nesting spots for smaller molecules. These small molecules are assigned coordinates within the hydrogel, and attached there using a laser beam that makes the hydrogel receptive to bonding with the molecule (or molecules) being inserted:

A laser shines into the hydrogel (yellow), attaching molecules to it at specific points in space (green)

Using this method, a team led by Ovsianikov and other researchers at Vienna University of Technology were able to demonstrate remarkably accurate three-dimensional control, down to a resolution of just 4 micrometers. In the 3D pattern featured up top, fluorescent molecules have been distributed throughout the hydrogel lattice in a pattern measuring just 180 micrometers across, demonstrating the incredible precision of the new technique.

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"Much like an artist, placing colors at certain points of the canvas, we can place molecules in the hydrogel – but in three dimensions and with high precision", exlained Ovsianikov in a statement.

The applications for this method of "3-D painting" are manifold. One attractive application, which springs to mind immediately, is the growth of biological tissues that require precise three-dimensional accuracy — blood vessels, for example. In the latest issue of Advanced Functional Materials, where the novel technique is described in full, Ovsianikov and his colleagues go on to suggest that the technique has potential applications in everything from studies of cell–surface interactions to sensing applications and drug screening.